Steam boiler



July 24, 1923.

w. NAKAGAWA STEAM BOILER Filed Nov. 29, 1918 5 Sheets-Sheet 1 July 24, 1923.

W. NAKAGAWA STEAM BOILER Filed Nov. 29, 1918 Sheets-Sheet 2 July 24, 1923.

11,462,763 w. NAKAGAWA STEAM BOILER Filed Nov. 29. 1918 5 Sheets-Sheet 5 Patented July 224-, i923.

WAICHI NAKAGAWA, OF KITAKU, JAPAN.

STEAM:

BOILER.

Application filed November 29, 1918. Serial No. 264,775.

To all whom it may concern:

Be it known that I, VVAICI-"I NAKAGAWA, a subject of His Majesty, the Emperor of Japan, resid'ng at No. 3A Tomijimacho, Kitaku, Osaka, Japan, have invented certain new and useful Improvements in Steam Boilers, out which the following is a specification.

This invention relates to improvements in steam boilers of the horizontal lire tube type, and more particularly in steam boilers having horizontal fire chambers below the boiler shell and a separate combustion chamber.

It is the general object of the invention to provide a boiler of the type referred to, which is simple and ethcient and particularly adapted for marine use.

In the drawing Fig. 1 is a front view of a construction embodying the invention; and

Figs. 2 and 3 are a side elevation and a rear view respectively thereof.

The arrangement preferably comprises a plurality of tubular lire chambers or furnaces a and a in parallel relation and surrounded by annularwater spaces. .ubove the furnaces is disposed the boiler shell 7), which contains the usual lire tubes 5 The arrangement of the furnaces and the boiler may be of any usual construction. The inter-space between the shell I) and the water spaces surrounding the furnaces a and forms a passage for the products of combustion. boiler is a combustion chamber which, by means of a horizontal partition 9, is divided into a lower chamber 7 and an upper chamber 8. The lower chamber is in communication with the interspace mentioned and the upper chamber is in communication with the tire tubes of the boiler. A. smoke box 6 at the front end of the boiler establishes connection between the interspace and the tire tubes.

The products of combustion are thus forced to pass from the furnace through the lower chamber 7, through the interspace and the smolre bot: Sinto and through the lire tubes of the boiler and then pass through the chammer 8 into the flue 10 and thus come into intimate thermal contact with the water in the annular spaces surrounding the furnaces a and a and with the bottom of the boiler shell I) aside from passing through the fire tubes.

At the rear of the furnaces and the In the combustion chamber 7 are mounted water drums 4.0 and 4.0 transversely of the furnaces, and in the chamber 8 are mounted two similar drums w and to". The drums are preferably connected in series by means 01' pipes 11. The lower drum 10 is connected l y a pipe m to the bottom or": the annular waterspace surrounding the two turnaces a and a while the upper drum to is connected by a pipe n to the boiler approximately in the plane ottthe normal water level. thereof. 1 also prefer to interconnect the upper part oi the annular water space surrounding the furnaces with the boiler substantially at the normal water level thereof, as by means of pipes 0.

Similarly the bottom of the annular water spaces may be in fluid connection, as by branches 1 and 2 and pipe (P, with the bot tom of the boiler shell 6.

In the chambers 7 and 8 I preter to use batlles 12 for deflecting the products of combustion against the water drums.

The arrangement described brings about a highly eiiicient heat exchange between the products of combustion and the water in the boiler and the thermal e'tliciency is increased by the different fluid connect-ions allowing convection currents to flow between different parts of the system.

I claim 1. A steam boiler comprising); two lower cylindrical elements having; each a furnace, an upper cylindrical element having a nest of fire tubes, smoke box at the front end of the said elements interconnecting the space between the three elements with the tire tube nest, a combustion chamber at the rear end of the said elements, a partition wall in the combustion chamber dividing it into an upper and a lower compartment in such a way that the lower ompartment is in communication with the said space and the upper compartment with the rear end of the fire tube nest, drums in the two compartments interconnected in series and fluid connections between the end drums and the said elements respectively.

2. Boiler construction according to claim 1 including baffle plates in the combustion chamber for directing the products of combustion against the drums.

In testimony whereof I afilx my signature.

WAICHI NAKAGAWA. 

